With a view of grasping contents of videos recorded in a recording medium or supporting a user who is to select or search a desired video, images that are extracted from a plurality of videos recorded in the recording medium and that are representative images representing the contents of the respective videos are often displayed together with titles in a list.
Examples of the representative images include a frame at timing at which a video scene changes and a frame in which a person or persons appear.
Patent Document 1 describes a method of displaying representative images prepared for a plurality of videos if specific frames are prepared in advance as the representative images and a request to display a list of the videos recorded in a recording medium is issued.
Each of Patent Documents 2 and 3 describes a method of extracting an image representing one moving image from a frame constituting the moving image.
Non-Patent Document 1 describes a feature extraction method for a color feature and a texture feature and a distance calculation method.
Non-Patent Document 2 describes a shape feature.
Non-Patent Document 3 describes in Chapter 3.2 a cosine similarity used as a similarity calculation method for a similarity between two keywords or texts if features of the comparison targets are both text data.
Patent Document 1: JP-A-2002-27410 (Paragraphs 0017 to 0060; FIG. 1)
Patent Document 2: JP-A-2005-209123 (Paragraphs 0040 to 0143; FIG. 1)
Patent Document 3: JP-A-2005-94756 (Paragraphs 0006 to 0035; FIG. 1)
Non-Patent Document 1: B. S. Manjuath and three others, “Color and Texture Descriptors”, (US), IEEE Transactions of Circuits and Systems for Video Technology, June 2001, Volume 11, Number 6, pp. 703-715
Non-Patent Document 2: Miroslaw Bober, “MPEG-7 Visual Shape Descriptors”, (US), IEEE Transactions of Circuits and Systems for Video Technology, June 2001, Volume 11, Number 6, pp. 716-719
Non-Patent Document 3: MIYABE Yasunari, TAKAMURA Daiya, and OKUMURA Manabu, “Method of Identifying Sentence Relation among Different Documents”, Information Processing Society of Japan (IPSJ), Special Interest Group of Natural Language Processing (IPSJ-SIGNL), July 2005, 2005-NL-169, pp. 35-42.